Gear-cutting machine



- H. HARTMAN GEAR CUTTING MACHINE Filed Nov. 30, 1926 Patented on. 9,1928.

GEAR-CUTTING MaoHiiiE.

NI E m erenr r HERBERT e. HARTMAN, or ROCHESTER; EW'iro-nmAssrenon To chanson worms, on];

, ocnnsrnn, new YORK, A; canteens-ion or Y Application filed November 30, 1912s. Serial No. 151,774,

for producing gears and particularly to machines of the intermittent or periodic indexing type, employing a rotaryannular face mill for cutting longitudinally curved tooth gears.

a machine which will enablethe cutting of all the teeth of-a gear alike and thus permit of )roducim matin ears which Will runrtoc gether smoothly and Without noise,

' Tntliemachine of'the type referredto,the toolis first rotated in engagementwith the blank to produce. a tooth or tooth space on the blank, then the tool and blank are relatively separated or disengaged, theblank is then indexed and the tool and blankare then re-engaged so that the'tool ope-rates upon a new tooth or tooth-space of the blank. The

' relative separation of" tool and blank and the indexing of the blank takes place after each tooth or tooth' space has been cut. The cuttin g,v \VIthClIEIWELL, indexin and return I constitute one cycle of operation of the machine.

HGI'GtOfOI'G, the meansfor imparting the periodic relative movement of separation b'etween tool and blank has beenactuated: by gearing selected merely to cause the separation and return at thecorrect time in the cycle, Without regard to thespeed of rotation'to the tool or the position of the cutting blades at the beginning of operation on thedifferent teeth In the, present invention the gears which a tuatethemeansfor causing the rela V tive separation and return are chosen not only with a View to secu-ringthe relat ve separation and return atthe correct time ingtl-ie cycle but are selected alsowith reference to "the sp'eedof rotation of the tool soas to have the tool always in tlie'saine position atthe commencement of operation on ZLIiy fOOth, thatis, as to have the samecutting blade of the tool commence torcut oneach tooth'of fllOblZUlli. Theselection ofthe gears in this manner permits of cutting all oftheteeth if thc blank alike with-the consequence that gears produced on a machine constructed-am cording to thisnvention will runtogether very quietlyandsmoothly'. H

. The purpose of this invention is accm-- plished by selecting the gears controlling the relative separation. and return With reference to the gears governing-the speed of'rotation of the so that tlie't'ool-Will make an: in

The present invention relateslt o machines" tegrlal number of revolutions during each;

cycle of machineoperation and consequently ent tooth or toothspace ofthe blank. fIi1 1 the preferred embodiment ofthe nventiom aset,

of speedchange-gears are incorporated the i I i I train driving the cutterspindle and a see-or which drives the eam which controls the periodic relati-ve separation between tool and 'feed change gears areii-nclu'ded in the train I vblank, and the two sets ofchange gears areI so] chosen" relatively to each other that the tool Will make an integral number 0f rotations for each revolution of the cam.- v

The principalobjects of-myinvention have already vbeen described. Otherobjects Willbe apparent hereinafter from the specification and the recital o-f the appended claims.

A preferred embodiment of my; invention is illustrated in the accompanylng drawing; in which: Y

igure 1 is an'isometric vieW of aspiral bevel gear o I present invention is embodied; and' Figure :2 is an enlargedfragmentaryplan view, showingthe connection between the-feed Y cam and the blank support.

The present after as embodied in one'type of' machine for producing spiral bevelgears; butit 'w illabe generatinm machine in which the nvention is. described hereintypes of bevel geargenerating mach-inesand in fact on any type ot'machine for producing gea 'slemployinga rotary tool and in partic'ular on machines employing rotaryto'ols havin a pluralityof equi-sp-aeed cutting blades.

Thejpresent application is intended to cover any uses ,,modifications; or adaptationsofthe invention which may fall yvithin the scope of the invention, or; the limits of the appended claims: v 7 l v ,In the lIlivChlnG llustr'ated,a rotary annula-rface mill 10 is employed. This tool 1.0

i's'proyi-ded Withaplu-ral-i-ty ofspaced cutting 1 I understooc l-that 1 i' .'lS employable on other,

ard' lethat is horizontally adjustable upon'a 1 c cradled-5 which is providedwith guide rails 16 which niiove in V -'sl'iaped Ways iii-the base 17 of the machine;

The blanlrB is seciired to a spindle, 2O wlri journaled n; blank l ie'acl fll whiel ie ad just-able upon the blank head carrier 22. The

' blank head carrier is in turn angularly adjustable upon m the machine;.1llustrated, is mounted for;

the frame or support 23 which,

angular inovementupon a stationary part formed integral with or secured to the base 17.

g In setting up the machine illustrated for operation, the tool and blank are first adjusted by means of the adjustments described .to

bring tool and blank into proper cutting position. The tool is then rotated in engagement with the bl ank. If'the toothprofiles are to be generated, a relative rolling movement is imparted betweentool and-blank by oscillation of the cradle and in tii'ned relation therewith,

during cutting, rotation of the blank spindle. After a. tooth oi'ftooth space has been cut, the tool and blank'a're disen nged,'in thenia-g chine illustratedby anangular movement of the blank support 23' on the base. The blank I is then indexed, thetool and blank are then l returned into engagelnentby the return move- Operates p n afnewtoo'th or tooth space of the blank lgq v ment of the blank support'23 and the'tojol then The! tool rotates continuously on its axis during'the'operatlon of the mach ne, being driven from the main drive shaft 25 byrne-ans of themiter gears 26, the shaft27, the-miter gears 28, the shaft 29 Whichhas a splined eo-nnection with the bevel pinion 30, the bevel pinion 30 and the bevel gear 31 which meshes therewith,t=he shaft 32,-the bevel gears 33 and 34, the shaft 35, the speed changegears 36 and 37, the shaft 38, the bevel pinion 39 and the bevel gear 40.which meshes therewith and which is secured to the tool spindle 12.

. T he periodic relative disengagement of tool and blankaccomplished by the pivotal move ment of the blank support 23 is controlled by s means of a feed cam 42 which is 'op'erative'ly 7 connected to the blank support: and wl11ch,'1n v the embodiment illustrated, is driven from .the

main drive shaft 25. The feed 05111142 is pro vide'd'with a cam slot onitsperiphery so con structedthat H1 onerevolution of the cann't-he machine completes one operating cycle. The'carn groove cooperates with a pin-4 4 secured to the lever H) which is plvotally mount-- to be indexed. w

ed onthe base; Thelever lti' is adjustably connected by means of a usual block and stud connection with an arm I46 which is secured to the frame 23. The cam'holds the blank in engagement with the cutter for a suflicient period to permit the completion of=one cuts 7 ting operation and then withdraws the blank for a period long enough to permit the latter "The. cam 42 is securedto a camshaft 46 which is journaled in the baseand which is driven from the main drive shaft 25 by means of the miter gears 48, the shaft 4 9, the feed change gears 50 and 51, the shaft 52,1the spur to gears 57 58 and 59, the shaft60, the worm "ears 53,54 amass, the-shaft 56, the spur.

61 carried thereby, and the worm wheel 62 which meshes with the worm and which secured to'the cam shaft 46.

Heretofore, the speedchange gears-3G and 37 have been selected so as to' give any desirable speed of rotation to the tool and the feed change gears 50 and 51 have been chosen simply to impart the the feed cam &2 so that theblank will be disengaged froin the tool, returned into engagedesired rate. of rotation to ment with the tool, and held in engagement.

one side ofa'toot-h move in the same circular path: If there is any error in the adjustment same blade might cut in dii'-- therewith,during the proper portions of the of the blades, it is reflected in the teeth out. V

l ler'eto-foreyahighor low spot caused by an inaccurateadjustmentof (i-blade would occur on difierentparts of the profile of different teeth beeause'the sameblade was'cutting o'n di-flerent'parts of the profile on different teeth. This made it extremely difiicult if not impossible to detect which of the cutting blades wasset inaccurately, while the occur 3' rence of a high or low spot on'difi'erent parts 7 i of thepro filesof different teeth is ofa source v p of noise in the operation of mating gears. I T headvance 1n the'present ln've'ntion consists in so selecting-the speed and the feed change gears relatively to each other that-the tool'rotates at a speed relative to the rotation of the cam such that "the same cutting blade is always inp'osition to engage'a tooth'of the 1 blank at the"connnencement'of each cutting operation whereby ferent teeth. NViththis arrangement of gearing, any errori'n the adjustment of a cutting blade can be" detected immediately, and cor-V reeted, since thehigh-or low spots caused by t-his'error in" setting will-occur in the same places on each o'fthe teeth I ployingthe present invention, all the teeth of a gear Will be cut alike and when that gear in mesh with a similarly out. gear the engage theblades always operate V onthe sanie partsof theprofi-les of the dif #In a machine emment and roll of the teeth of one gear upon anotherwill be extremely smooth and quiet.

The purpose of the present invention is accomplished in the machine illustrated by so selecting the feed change gears 5O and l 51 with relation to the speed change" gears 36 and 37 that the tool 10 will-make an integral number of revolutions duringone, rotation of the cam 42, whereby the tool 10 will inakean essee-2 I integral number of revolutions. during one cycle of operation. of the machine and so the blades of the tooliwillialways be in the-ea e position in the same part of the cycl'e 'of' operation upon any tooth.

In the machine illustrated, the-generation of'the tooth profiles is obtained through a movement of' the cradle 15 on its axis and arotation of the-blank B on its axis. The cradle movement i s derivedfroin the shaft- 56 through a reversible shaft whichmay be driven in opposite directionsfrom the shaft 56 by means, on, the one hand, of a pair of spur gears 66 and 6'? or, on the other hand, of spur gears 68 and 69 and the idler T0;

The reversibleshaft 65 carries a spurigear Tl whiclrmeshes witha spur gear 72whi h is secu'red'toa cross shaft 7' 3 which is journaled in the bases Theshaft drives,

through the miter gears 74:, the worm shaft which carries-a worm 7G which-meshes with a worm wheelsegment (not shown) whlchjissecured to'the cradle 15.

The rotary movement of the blank spindle,

'd'ur-im cuttin isalso derived from the shaft 56 through the reversible s-haftcs, the reversible; shaftd'ri vin i as alread described the cross shaft 7 3 through the gears?- 1 and 72 and the crossshaft Y3 carrying a miter gear SOWVl'llGh inesheswith a miter 81. which [is secured to a shaft 82'. .The shaft 82 carries adjacent its outer end aspur: gear 83 whichmeshes with a spu'rgear 84 which in turn meshes with a spur gear 85 secured to a shaft S6. The spur gears 83, 84 and 85, constitute aset ofratio change gears governing the ratio of roll between blank and cradle, while the spurgears7 1 and "F2 constitute a set of roll change gears governing the amount of the roll. -'Fhe shaft 86 is connected withanalignedshaftS'i', by means of aset of "difl'erentialgcars' (not shown) which I are housed withinthediilierential housing '88;

lheshaft 871- drives the vertical shaft'89, about the 'aXis'of'which-the pivotal movement I of the blank support'23 takes place, through the miter gears-89 The'shaft 89, carries a .bevell gear 90 which meshes witha bevel gear- -91 whichisisecuredzfto the diagonal shaft 92 which drives through the miter gears 93,-

i on

the telescoping shaftF'Qil; .The shaft- 94 carriesaspur gear '95 -.which meshes with a spur gear'96 which-is mounted upon a stub shaft 97 which also carries .a spur gear 98 which inesheswi'th a 'spurgear 99 on'the shaft 100. The gears 95,96, 98' and99 form a set'of' index change gears governing the number of teeth to be out on the blank. The shaft 100 drives a worm shaft 101 through a pair of miter gears 1'02. Se-curedgto the worm shaft 101 is'a worm 103 which meshes with a 'w'o'rni wheel lO lwhich is-fastenedtothe blank spindle-20. Throughthe gearingdescribed,

' the b'lanltis rotatedih timed 'relationwiththe machine illustrated, an additional algebraic rotation is periodically imparted .to the blank spindle for the purpose of'indexing the blank. This additional rotation may increase or-de- *crease the ordinary cutting rotation of the blankspin dle so as to accelerate orretard the same. The additional algebraic rotationis derived from-the shaft- .56. .This shaft ion 105 which meshes with a'hevel gear' 106 secured to a vert calsha'ft 107' wh ch. carries whiclrmeshes with a bevel gear109.upon{ the 1 carries intermediate its. length a bevel. pin- 80 J adjaeent'its lower end a bevel pinion; 1 08 I horizontal shaft 110, The shziftllO-tarriesj .adjaeenti ts outer end a spur gear lll'which -p drives the spur gear 112jby means. ofithe'spur gear 113. Thespur gear 112 is a-dapted'to be periodically connected with the differential housing 88, thisfconnection. occurring during the time thefblank isi disengaged. fromythe tool. The operative connection. of the spur; gear 112 with the difierentia'l' housing 88 causes aninc'reaseor decreasein the speed of rotation of the shaft'SZ, thus increasing I or decreasing the "speed of rotation ef t-he blank spindle and the blank carried thereby and thus indening. therbilanl' n; j

- During the cuttingoperation,-the differential housing 88 is locked against rotation.

flhe means for locking the difierential-hous"1 100 iiig. against'rotation during cutting: and the means for-connecting the spurigear 112 with thishousing periodically may be of. any suitable form. 'lngeneral, the machine illustratedis constructed andoperates in-the same way-as-the machinede'scribed in the copend- "ing application. of "Ernest Head Serial -'No. 113,532, filed JuneB, 1926,;be1ngcap'able,-

therefore, of producing gears of highes t acfcu-i'ac-y in; tooth spacin-gand profile.

One of the locking levers for the -'clifieren-' tialhousing is shown onthe. drawings/ofthe present application in released position. This lever'is indicated at 1 15. For withdrawing this lever from locking position, a bellcrank lever 116 is employed, as in th'e machineiof the whichis secured tothe base-0r the machine.

The bell orank'leve'r llfi' cai'r-ie's onone end .120 lever '115 and :on thefother' end a roller 1'19 the; periphery jofT-thercam .diSc 120.."-"-

a block 118- which engages with {the locking which rides on The cam dis c 120' shaft 46 l and a1 lug or nose on the periphery ofthis "cam disc is adapted fto engage-the roller-119 once in eachrotation of the shaft. 46 to rock; the lever-116i and'iwithdraw-the is secured on the eam,

115m. application referred to. Therbellcranlt lever 116 is pivota'lly mountedupon an arnrll? :locking lever 1-15 from locking engagement with the difierential housing 88 to permit of the indexing operation. The indexing operation is thus controlled from the cam shaft e6.

The direction ofrotation ofthe reversible shaft 65is alsocontrolled from tlie'cam shaft 46, the'cain disc 120 being provided on its fa'ce'with a cam groove 121' which cooperates with a roller'secn'red to a lever arm 122 which pawls 125 Whichai'e pivotally mountedon either side of the disc 126 .and which arev adapted respectively to alternately'engage ratchetteeth 127 which are formed on the sleeves of the gcars69 and 67. The disc 126 is secured to the shaft 65 and the sliding of the slide123 under actuation of the lever 122 and cam 121 causes this disc to be coupled alternately with the gear (Wand withthe gear 769, thus periodically reversing the direction may beemployedadvantageously also even;

of rotation of the shaft and of the cradle and main-drive to the blank'which are actu ated from this shaft. 65.1

.This mechanism forms one type of'reversing mechanism, (described morezparticularly in U. S. Patent No.

1,203,608, Gleason ,et 211., November 7, 1916) of which any usual or suitable type may be employed on the machine described. I

" The present invention has been described in 2 connection with a machine employing an indexingmechanism of the universal or worm and worm wheel type. It will be understood, however, that it isapplicable also to machines on whicha notched plate index and indexing mech anism is used,- the essential purpose of the present invention being toso time the cutter rotation inthe cycletofoperat-ion that the blades of the cutteralways out in the-same places, that'is on the same parts of the profiles of all the teeth of the blank. i J The present invention is not restricted to machines employing annular face mills, but may be used also where a CllSCIDllllIlg cutter is employed. Indeed,1since itis'always de sirable to produce allthe teeth of a gear under the same: conditions, the present; invention where "tools having a continuous operating surface are used, as, for instance, 1n grinding f machines and the term tool as employed in the'claims is intendedto cover bothtools V having a plu'ralityof cutting blades and-tools having a continuous uninterruptedoperating.

surface. 1

With thepresent invention gears will be cut :more accurately, sincean immediate check is afforded to enable the prompt detection and 'GOIIQCtlOILOf any serious error in the setting of the cutter blades; the spacingfi'om tooth of the profile and mating. gears will always mesh in the same way thouglrfdiiferent teeth be in engagement at difierent times. Thisin- ,vention, therefore, makes formore accurate,:

to tooth on a'gear will be thesaineon all parts 7 more smoothly running, and more quiet gears.

WhilejI have described'my invention 1111' connection. witha specific'stru'cture, it is to.

be, understood that the invention is capable of various further-V modifications, adaptations and uses, without'departing from the intent of th e invention or the scope of the following claims, and that thlS QPPllCl-WlOH is in tended to cover any adaptations or einbodiments, following, in general, the principles of the inventionand includingsuch depar-' so I tu'res' from the present jdisclosuregasicome within known orcustomary pract ce lll 'tl'le fall within the scope of the invention or the limits of the ap] 3ended.- claims.--

Having thus described my invention, what I claim is:

' 1. In a gear cutting machine of the peri-' geariart and as may be applied to the essenitial features hereinbefore set forth and as odicallyindexing type, a tool support, a blank support, a rotary cutter, having aplurality of eqnidistantly spaced cutting bladesar-J ranged on its periphery,rotatablymounted on said tool support, means for imparting a means for periodically effecting :a 1 "relative separation between the tool and :blank to permit of indexing the blank, and gearing governing the operation of said last named means, saidgearingbeing. so selected as to permit of the toolmaking an integral number of revolutionscluring each cycle of operation of' themachine wherebyithe same blade ofthe cutter commences to cut at the begincontinuous rotary movementqto the tool,-

ning of operation on each-tooth of the blank.

. 2. In a gearcutting machine of the peri odically indexing type, a tool support, a blank I support, a rotary annular cutter having a plurality of "cquidistantly spaced: cutting blades arranged on its periphery, rotatably 'IHOUHtQCl on said support, means for imparting a continuous rotary 1 movement to the tool, means for periodically effecting a relativeseparation between thetool and blank supports to perniitof indexing: the-blank,

and gearing governing the operation-of said last named means, said gearingbeing so se- ,lected'as to permit of'the tool making an integral number of revolutions during each cycleiof operation of the machine whereby the same blade of the cutter commences to cut at the beginning of operation on each tooth of the blank. 7

3-; In a gear cuttinginachine, of the-periodically indexing type, a tool support,.a blank support, a blank spindle 'ournaled; in said blank support, a rotary cutter zha'vinga" plurality of y equidistantly spaced cutting bl'adesarranged on its periphery, rotatably gearing being so selected as to permitof the mounted on saidtoolsupport, means fOljlIIh parting a relative rolling motion between the tool. and blank to generate-the tooth profiles during cutting, means for periodically index. ing the blank, means for periodically etlecting a relative separation-between. the tool and blank supports to permit of indeking the blank, and gcarlnggoverning the operas tion of said last named means, said gearing being so selected as to permit 0t the: tool making'an-integral number of revolutions during each cycle of operation of themachine Whereby the same blade of the cutter commences to cut at-the beginning of operation on" each toothoftheblank.'-' I 4. In a gear cuttingmachine of the periodicarlly indexing-type, tool support, a blank support, a blank spindle journal-led in said blank support, arotary annular cutter, having a plurality of 'equidis'tantly spaced cuttingblades arranged: on its 1 periphery, rotatablymounted' on-sarcl tool support, means for imparting a, relativerolling motion bee,

tween: the tool and blank. supports to gen- 1 crate. the tooth profiles during cutting, means for periodically indexing the blank, means for periodically effecting a relative separa-i tion between the tooland blank supports to permit of 1IllGX111g,- and gearing. governing the operation of said last named means, saidtool making an integral number of revolu trons during each cycle of operation of the machine whereby the same blade of the cutter commences tov cut at the beginnln-g of operationupon each tooth ot' -the blank.

- In a machine.for sproducinggears a tool support, a blank support, a tool spindle journaled in said tool support, a rotary cutter, provided with a. plurality of spaced cutting blades, mountedon said tool spindle,

a main. drive shaft, gearing connecting-said main drive shaft to the tool spindle include. 1I1g a set or" change gears governing the speed o1 rotation of thetool', means for pf10dlcally indexing the blank, acam and acam shalt-101" periodically eilect-ing'a relative separation between the tool and blank set-p port to permit of indexingtll'e blankand for returning the toolaand'blank into engagement for operation on another"toot-h,'v and gearing connecting said main drive 'slmatt" with said cam shafik'incl'udinga set of change gears, said change gears being: soppropor itron'ed to the: change gears governing the rotation of the tool that the tool makes an; integral number of revolutions d urmg'each rotation "of the camshaft;

6 In a: machine for producing gears, a tool support, a blank support, a tool spi ndle journaled in said tool support, a rotary an nular cutter, provided With a plurality of spaced cutting bladesmounted on the'too'l spindle, a maln drive sliiaft, gearing connecting said main drive shaft to the-tool a cam and a: camshaft for periodica ly etfecw rotati'or of said cam shaft-:1-

meains' for imparting a relative rolling move-g o blades, mounted-ion: the tool, spindle, means o therebyfor periodically spindle including a setiofchangegears ov... erning the speed of rotationiof the tool, means. for periodically inder g the blank;

ing a relative separation between thetoo'l and blank supports to perm t of indexin "the blank an: tor returning the tool and blan t into: engagement for operation on another tooth, and earingrconnectlng said cam slrazfit' 'ot-i change gears, said changegears being. so proportioned to the. cl-lange gears governing 1 theer'otatio-n of the tool that the tool makes Jana integral: number-ct revolutions diuri'ng. eacleiz L 7'.'In-- amaclrine for producing gears', 'al: tool; support, ablank support, atool spindle;- journaledrin said tool support, a rotary an: nular tool mounted on said toolspindzle,

ment between the tool and blank suppcr-tsto g generate'the ltooth profiles, means for period--- I ically imparting an.-indeXing-motion to the: blank, means for rotating "the, tool spindle A including a set of change 'gears,=: a shaftp meansoperated thereby tor periodically ef.- fecting a relative separation 'b'etween-the-wtool and blank. supports toppermit of i rcleninmw the blanlgmeans operated from said slit for goyerning the :rolling movement, means operated trom: salcl shaft governlngi the 111-" dexingsof theblanlgand: gearing; tor-rotating said shaft, including a set of'change gears so proportioned; to thechange gears governing the rotation: of the :tool spindle that the tool makes an integral number 0t revolutions during each cycle of. operation ofthe" ma- 8. Inamac'hinelorprol 'cing'gears,-a tool support, a bl'ank support, a tool spindle'jour 'i L J V naledl-in said tool suppord a'rotary'puttcrt. provided With a plurality of spacedicutti'n for imparting aj rela-tiverollmg movement between the tool and blank. to generatethe;

set of change-gears so proportioned to. the

change gears'governing the rotationof tool spindle that the tool makesia-n integral v number of revolutlons durlng eaol-rcycleot operation orthe machine. 7 9; In a machine for producing gears, 21; blank support, a blank spindle -journaled'lfl therein fa tool" support, a tool spindle]jour n'aled therein, a'r'otary annular'toolinountecl.:. I

h said l-nirin drivelshaft including a-fset 75 i 1o 3 change gears so selected-relativeto the gears driving the tool spindle that the tool makes indexing the'blank, means actuated on the tool spindle, an oscillatory cradle upon which one of said supports is mounted, gearing for drivingthe tool spindle, a shaft, means actuated by rotation of saidshaft for oscillating the cradle, means for periodically by rota.- tion of said shaft for periodically effecting vr a relative separation between the tool and i therein, a tool a plurality of spaced cutting blades, mounted permlt of indexing, and

blank supports to shaft including a set of means driving said an integral number of revolutions during eachcycle ofoperation of the machine.

10. In a machine for producing gears, a

blank support, ablank spindle journaled support, a tool spindle journaled therein, a rotary tool, provided. with on the tool spindle, an oscillatory cradle upon which one of said supports is mounted,

gearing for driving the toolspindle, a shaft,

means actuated by rotation of said shaft for oscillating the cradle, means for periodically indexing the blank, means actuated by. rotationof saidshaft for periodically effecting a relative separation between the tool and blank supports to permit of indexing, and

naled therein, a

means driving saidshaft including a set of a ge a driving the tool spindle that the tool makes an integral number: of revolutions during v each cycle of operation ofthe machine.

11. In a machine for-producing gears,- a

:blank support, a blank spindle journaled therein, a tool support, a tool spindle jourwhich one of said supports is mounted, means for driving the tool spindle including a set of change gears governing the speed of rotation of the tool, a cam shaft, a cam mounted thereon having an operative connection With one of said supports for periodically efe Jfectinga relative separation between saidsupp'orts, means :operated from said cam shaft for controlling the movement of the cradle,

ting, means blank, and means for driving said cam shaft in timed relation Wit-h the cradle during cutfor periodically indexing the including a setof changegear's so proportioned to the change gears governing the speed-ofrotation' of the tool that the tool makes an integral number ofrevolutions for each rotation of the cam shaft.

12. In a-wmachinefor producing'gears, a. blank support, a blank spindle journaled therein, a tool support, a tool "spindle" jour naledtherein, a rotary tool, provided with a plurality of spaced cutting blades, mounted on the tool spindle, an oscillatory cradle uponiwhich one of said supports ismounted,

means for driving thetool spindle including a set. of change gears governing the speed of supports,

' change gears 'ears soselected relative-to the gears rotary annular tool mounted on the tool spindle, an'osc'illatory cradle upon means for rotating the blank spindle' ed on the tool I upon which one of saidsupports is mounted,

rotation of the tool, a camshaft, a cam'mounted thereon having an: operative connect on with one of said supports for periodically ef- V fecting a relative separation between said means operated from said cam shaft,,for. controlling-the.movement ofthe V cradle, means for rotatingthe blank spindle,

in timed relation with the cradle during cut ting, means blank, and means for driving said cam shaft.

tioned to the change gears-governing thespeed' of rotation of.the "toolthat the tool makes an integral number 'ofrevolutions for actuated by the rotation of said auxiliary shaft for periodicallv effecting Y a relative separation between said tool and blank supports, a reversible shaft,gearing operativdy cradle, means'actuated by rotation of said for periodically indexing the including a set-of change gears so propor-- 05 connecting said reversible shaft with, the

auxiliary shaft for controlling the direction r of rotation of the reversible shaft, gearing. operatively connecting the reversible shaft spindle in timed relation'with the'cradle dur with the blank spindle for rotatingthe blank ing cutting, means for periodically impart ing an additional algebraic movement to the blank spindle during the relative'separation of tool andrb'lank support to index the blank,

means for locking said last namedmeans.

against operation during cutting, means operated from said auxiliary shaft'for controlling said locking' means, and gearing connecting "said auxiliary shaft with said main drive shaft including a set of change gears so proportioned to the change gears governing the rotation of the tool spindle that the tool makes an integral'number of revolutions during each cycle of operation of the machine. I V V l 1 41 In a machine-for producing gears, a

blank supportfablank spindle journaled therein, a toolsupport, a tool spindle jour: naled therein, a rotary-cutter, provided with a plurality of spaced cutting blades, mount; spindle, an oscillatory cradle a main drive shaft, gearing connecting the main drive shaft with the tool spindle in eluding afset of changegears governing the speed of rotation of the tool, an auxiliary shaft, means actuated by rotation of said auxiliary shaft for periodicallyeffecting a v relative separation between the tool and blank supports, a reversible shaft, gearing operaint tively connecting said reversible shaftwith the cradle, means actuated by rotation. of said auxiliary shaft for controllingthe direction of rotation of the reversible shaft, gearing operatively connectingthe reversible shaft with the blank spindle for rotating the blank spindle in timed relation with the cradle during cutting, means for periodically imparting an additional algebraic rotation to the blank spindle during the relative separation of tool and blank supports toindex the blank,- means for locking the last named means chine.

15. In a machine for producing gears, a blank support, a blank spindle 1ournaled therein, a tool support, a tool spindle yournale'd therein, a rotary annular tool mounted on the tool spindle, an oscillatory cradle upon which one of said supports is mounted,-a main drive shaft, gearingconnectingsaid main drive shaft with the tool spindle ineluding a set of change gears governing the speed or rotation of the tool, a cam shaft, a

cam mounted thereon having an operative connection with oneof said supports for periodically effecting a. relative separation between said supports, a reversible shaft, gearing operatively connecting the reversible shaft with the cradle, asecond cam on said cam shaft governing the direction of rotation ofthe reversible shaft, gearing operatively connecting said reversible shaft withythe 7 blank spindle for rotating'the blank spindle intimed relation with the cradle during cutting, means for periodically imparting an additional algebraic rotation to the blank spindle during the relative separation of the against operation during cutting,'additional cam means carried by sald cam shaft for gov-J shaft including a set of change gearsso'proportioned relative to the change gears gov-; ernlng the speed of rotation of the toolthat lutionsduring one'rotation of the cam shaft. 7 16. In a machine for-producing gears, a blank support, a blank spindle 'jo'ur'nale'd therein, a tool support, a tool spindle journaled therein, a rotary cutter, provided with a plurality of spaced cutting blades, mounted on the tool spindle, an oscillatory. cradle upon which one of said supports is mounted,

'tool andblank supports to index the blank,

means for locking said last namedmeansgfia erning said locking means, and gearing connecting said cam shaft wlth said main ClIlVG' the tool makes an integral number of revoa main drive shaft, gearing connecting said main drive shaft with the tool spindle in cludlng a set of change gears go vernlng the speed of rotation of the tool, acam shaft, a

cam mounted thereon having an. operative connection with 'oneof said supports for periodically effecting a relativeseparation between saidsupports, a reversible shaft, gearlng' operatively connecting the reversible shaft with the cradlega second cam on said cam shaft governing the direction ofrotation of the reversible shaft, gearing operatively connecting the reversible shaft with the blank spindle for rotating the blank spindle in timed relation with the cradle during cutting, means for periodically imparting an additlonal algebralc rotation to the blank spindle duringthe relative separation of the tooland blank supports to index theblank means for locking said last namedmeans against operationduring cutting, additional cam means carried by said shaft for governing said locking means, and gearing connecting said cam shaft with said main drive shaft including a set of change gears "so proportloned to the change gears 'governlng the speed of rotation ofthe tool that the tool"- ing each rotation of the camshaft.

HERBERT enmrMank makes an integral number of revolutions dur- 

